The invention relates to a door for a motor car and to a method for production thereof.
German Patent Document DE 100 22 360 A1 discloses a door and a method for production of a door in which a door support is provided with at least one metal carrier element that can be formed in a one-part or multi-part way and which is provided at least partially with plastic. The connection point of one profile to the other profile is overmolded with plastic in order to produce a corresponding connection of the two components. The respective metal carrier element can thereby be a part formed with internal high pressure that is joined with other support parts to form a door frame structure.
U.S. Patent Document 2008/0038576 A1 discloses a tubular metal structure component formed by means of internal high pressure and on which two vertical standing elements composed of plastic are sprayed. The structural component is used in particular as a front end carrier.
German. Patent Document DE 103 26 768 A1 discloses a combined internal high pressure forming-injection molding process, by means of which a hybrid component is produced from a metal tube and plastic. German Patent Document DE 10 2007 017 420 A1 also shows an internal high pressure forming-injection molding process, wherein openings are formed in the metal carrier tube by means of a punching die. The same process can also be seen in German Patent Document DE 10 2007 060 628 A1 in which mesh-like structures composed of plastic are sprayed on a metal carrier tube in order to form a composite component.
Exemplary embodiments of the present invention are directed to a door for a motor car and a method for production thereof that are optimised with regard to the weight of the door and the integration of further function areas.
In order to create a door optimised with regard to its weight and the integration of further function areas, exemplary embodiments of the present invention provide at least one metal carrier element that is produced as an internal high pressure formed part. Indeed, such an internal high pressure formed part has the advantage that it can be designed to be exceptionally adapted to stresses so that, for example, excess material accumulations or similar can be avoided. It is instead possible with such internal high pressure formed parts to easily adapt the form and/or cross-section thereof to the force and torque pattern within the door in order to consequently avoid excess wall thicknesses or similar, which would lead to an increase in the weight of the door. Furthermore at least one metal reinforcement part and a support part are attached to the metal carrier element. This can be carried out, for example, during the internal high pressure forming—for example by hydro-clinching. Likewise, a connection can obviously also be produced between the metal reinforcement part and the support part and the corresponding metal carrier element through the plastic. The at least one metal reinforcement part and support part can thereby be reinforced according to a further embodiment of the invention through the plastic and/or attached to the metal carrier element and/or provided with at least one function area. In other words, the plastic can be used particularly advantageously to reinforce corresponding components, to attach them to others or to provide them with further function areas such as screw slots or other bracket elements, mounts or similar in order to fix for example further components such as loud speakers or similar.
A further advantageous embodiment provides that the at least one metal reinforcement part and/or support part is formed as a pultruded profile or organic sheet. Such components are extremely rigid in spite of lower weight.
A further advantage of the door according to the invention is that, due to the design of the at least one metal carrier element as an internal high pressure formed part, further functions can be integrated into the door support. A corresponding function part can be connected to the metal carrier element, for example, in the internal high pressure forming process, in which the metal carrier element is formed. In addition, during the internal high pressure forming, corresponding mounts, bracket elements or similar can be incorporated into the metal carrier element in order to create function areas for the attachment of further components or similar. In addition the hybrid construction has the further advantage that, through the combination of different materials, simultaneously light and rigid components can be produced. It is possible for example, in spite of all requirements upon load being fulfilled, to save around 1.5 kg in comparison with conventional doors. In addition the door fulfills particularly high side crash requirements through load-optimised constructions. A further advantage of such hybrid components is that plastic can be obtained at a far lower price than other metals that otherwise would have to be used for function integration, whereby this applies not only for the semi-finished product but also in production. A further advantage of plastic is that it is not prone to corrosion, unlike a multitude of other metal components.
According to a further embodiment of the invention the door support is produced in a combined internal high pressure forming and injection molding process. The internal high pressure forming and the injection molding are thereby characterised initially in that these are proven production methods that can be brought together in one installation. A considerable reduction in the manufacturing tolerances in comparison with other production methods can thus be achieved. The combined internal high pressure forming and injection molding thereby has the further advantage that only one tool is required This allows, inter alia, the cycle times, the investment costs, the space requirement for the system technology and work steps and subsequent processing steps to be spared.
According to a further embodiment of the invention the door support is connected on the outer side with an outer panelling part and on the inner side with an inner trim part facing the interior of the motor car. This shell mode of construction allows, amongst other things, a modular construction principle, so that easy adaptation of doors for different series is possible. It constitutes, after all, an extremely requirement-based and flexible possibility for producing doors.
Furthermore, it is advantageous if the at least one metal carrier element extends at least in areas along a respective lateral edge side and along a lower edge side of the door. The at least one metal carrier element formed through internal high pressure forming and provided with plastic thereby facilitates the creation of an exceptionally stable frame, to which further part components or similar can be fixed for the production of corresponding functions.
According to a further embodiment of the invention the at least one metal reinforcement part and/or support part is/are connected through hydro-clinching to the metal carrier element. The hydro-clinching can thereby be carried out preferably within the scope of the internal high pressure forming and injection molding process.
According to a further advantageous embodiment the metal carrier element has different cross-sectional forms and/or wall thicknesses over its progression. A particularly weight-favourable component form can hereby be achieved.
According to a further embodiment of the invention at least one reinforcement element and/or function part is integrated into the plastic. By integrating a reinforcement element into the plastic, a relatively weight-favourable reinforcement of the metal carrier element can thus be achieved, which for its part can be designed with corresponding weight reduction. In addition the plastic is particularly favourably suited for integrating further function parts and thus creating a simple attachment possibility for further components.
In addition it has proved advantageous if an energy absorption element, in particular a structural foam, is arranged in at least one hollow profile of the door support. Through such an arrangement of an energy absorption element it is possible to improve for example the crash behaviour of the door in a simple and advantageous way.
According to a further advantageous embodiment the metal carrier element is reinforced by at least one fibre reinforcement and/or by cables, in particular as a mesh structure in an organic sheet and/or as integrated cable reinforcement. This results in a particularly favourable stiffened metal carrier element. It is further advantageous in this connection if the fibre reinforcement and/or the cables are connected by mechanical connecting means, in particular by riveting, screws and/or slotted hydro punch rivets with the metal carrier element. This results all in all in a particularly favourable connection.
According to a further embodiment of the invention the fibre reinforcement and/or the cables is/are tensioned with the intermediary of an underlay element against the metal carrier element. This results in a particularly large format fixing of the fibre reinforcement and/or the cables to the metal carrier element.
According to a further embodiment of the invention the metal carrier element is formed from an extruded profile. This can thus be designed particularly simply and adapted to loads.
In addition it has proved advantageous if the door support or the metal carrier element is subjected to a heat treatment process after the combined internal high pressure forming and injection molding process. This heat treatment process can be carried out, for example, within the scope of a painting process—for example during cathodic immersion painting. The strength and crash-expansibility of the door support/the metal carrier element can be further improved.
According to a further embodiment of the invention a lock area of a door lock of the door can be formed by the metal carrier element. This allows a simpler or easier design and assembly of the door lock.
In accordance with an exemplary method of the present invention, the at least one metal reinforcement part and/or support part are attached in the combined internal high pressure forming and injection molding process to the metal carrier element. This simplifies the production process for the door.
Finally, it has proved advantageous if the metal carrier element and/or the metal reinforcement part and/or the support part is/are preformed before being introduced into the internal high pressure forming and/or injection molding tool. Correspondingly high degrees of forming can thus be achieved for example.